Molten salt media carbonization

The direct, one-step production of DMF from carbon monoxide, hydrogen, and ammonia has also been reported. A mthenium carbonyl catalyst is used, either ia a polar organic solvent (20) or ia a phosphonium molten salt medium (21). 

Fused Salt Electrolysis. Only light RE metals (La to Nd) can be produced by molten salt electrolysis because these have a relatively low melting point compared to those of medium and heavy RE metals. Deposition of an alloy with another metal, Zn for example, is an alternative. The feed is a mixture of anhydrous RE chlorides and fluorides. The materials from which the electrolysis cell is constmcted are of great importance because of the high reactivity of the rare-earth metals. Molybdenum, tungsten, tantalum, or alternatively iron with ceramic or graphite linings are used as cmcible materials. Carbon is frequently used as an anode material. 

There are two other methods for producing ferrite powders that deserve attention molten-salt synthesis and shock-wave loading. In molten-salt synthesis, Fe203 and the corresponding carbonate, oxide, hydroxide or nitrate needed to produce the ferrite phase are dry blended with a mixture of NaCl and KCl. This reaction mixture, in a Pt crucible, is placed in a furnace at 800-1100 °C for lh the chloride solvent is melted and provides an efficient heating medium for the reaction. After cooling, the solvent is separated from the ferrite by dissolution in water. The product can be finally collected by filtration. Ba and Sr hexaferrite powders have been prepared by this method (Arendt, 1973). Submicron, high-quality crystallites with a low ferrous content were obtained. 

PT has also been synthesized through anodic oxidation of thiophene or bithiophene in molten salts such as AICI3 and l-methyl-3-ethylimidazolium chloride, and films have been deposited on Pt, W, and glassy carbon electrodes [42], PT has been electrochemically synthesized by several groups, where the main conditions studied were the electrolytic medium, the monomer concentraticai, and the employed electrodes [40, 42-45]. 

The reduced molten salt mixture containing typically 62% Na2, 8% Na2S04, 25% Na2C03, and 5% unreacted carbon and ash is continuously discharged from the reducer vessel and quenched in an aqueous slurry. Soluble constiments of the melt are dissolved in the aqueous medium, which is then filtered to remove unreacted carbon and ash. The clear liquor is reacted with carbon dioxide gas in a series of sieve tray columns to produce, ultimately, a solution of sodium carbonate and a gas stream containing H2S and CO. This gas is fed to a conventional Claus plant where the H2S is converted to elemental sulfur. The sodium carbonate solution is recycled to the spray dryer as the active absorbent for SO2. 

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